<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<style>
    div{
        width: 0;
        height: 0;
       border: 40px solid;
       border-color: transparent transparent red;
    }
    div:nth-child(2){
       
        width: 0px;
        height: 0px;
        border: 40px solid red;
        border-color: orange red black yellow;
    }
    div:nth-child(3){
        width: 100px;
        height: 100px;
        border: 40px solid red;
        border-color: orange red black yellow;

    }

</style>
<body>
    
    <div>

    </div>
    <div>

    </div>
    <div>

    </div>

    <div style="
    width: 0; 
    height: 0; 
    border:50px solid cornflowerblue;
    border-right: 50px solid greenyellow; 
    border-left:  50px solid greenyellow; 
    border-radius: 50%;
    transform: rotate(-45deg)
    "
  >
  </div>
</body>
</html>